Based on the assumption that emotion is acquired, this article examines and analyzes the mental contents and neural basis of emotional experience and sensory feeling（e.g. pain, hunger，taste，smell and so on ) by referencing the existing theoretical viewpoints and experimental results. It is argued that emotional experience and sensory feeling are all the compound feelings that consist of cognitive representation（referring to all kinds of discriminative sensations and all kinds of mental representations based on them）and affect representation (only two conscious qualities, pleasure and displeasure that respectively carry the mental states of likes and dislikes,), and the affect representation is the core components of emotional experience. And then it is assumed that the core component of emotional experience，at the level of neural activity，originates from the conditioned response of the affect component of sensory feeling, based on the separability of cognitive representation and affect representation in emotional experience and sensory feeling as well as the homology in neural basis between the affect representations in emotional experience and in sensory feeling. And some specific performances of cognitive representation, affect representation in emotional experience, and related mental phenomena are discussed, from here it infers that objectification of affect (projects conscious qualities and liking or disliking states of affect onto the perception of body or outside object) is an important mental mechanism in emotional experience.

INTRODUCTION： For a long time, most psychologists believe that human is born with a few basic emotions(usually fear, anger, sadness, happiness, disgust, and interest）,each basic emotion is a set of particular global response(including body arousal, subjective experience and behavior or action potential）generated by innately set independent brain devices that is genetically determined products of evolution（but is influenced also by experience）, while some more complex emotions such as shame，pride and guilty may be the combinations of several basic emotions（e.g., Colombetti, 2009; Damasio, 1994; Damasio, 1999; Ekman,1980; Ekman, 2003; Izard & Malatesta, 1987; LeDoux, 1998; Tomkins, 1962）. This view is, after all, just a theoretical assumptions, and some meta-analyses do not support that there are the specific brain structures that correspond to the different basic emotions（Murphy, Nimmo-Smith, & Lawrence, 2003；Phan, Wager, Taylor, & Liberzon, 2002）. In the last decade, emotion psychologists Russell and Barrett have questioned the basic emotion view from the aspects of neuroscience，phenomenology，linguistics and so on（Barrett, 2006; Barrett, 2006b; Barrett, Mesquita, Ochsner, & Gross, 2007; Russell, 2003, 2005, 2006, 2009; Russell & Barrett, 1999）. They argue that the set of particular response of each typical emotion may be a stable pattern formed postnatally by some related responses that generate by different mechanisms, and believe that the progress in the science of emotion has been blocked by the basic emotion assumptions. They suggest that the core affect that consists of valence（pleasure-displeasure）and arousal constitutes the most basic building block of emotional life，and they are basic and primitive, while the emotion is produced from the attribution or conceptualization of core affect when the core affect change in the reaction to a event. And they argue that the task of emotion science is to make empirical researches and interpretations on the each component of emotion as well as the relationship between them.

I agree with Russell and Barrett’s basic view that emotions arise from acquired mechanism and their opinion about the task of emotion science. However, I think they interpret the core affect as basic and primitive building block of emotion which may pay too much attention to the correlation between valence and arousal, while ignoring that they may also arise from different mechanisms. In the first two chapters,this article examines and analyzes the mental content and neural basis of emotional experience and sensory feeling, and argue that they are both the compound feelings that consist of separable cognitive and affect representation which come from different sources (the “affect ” in this article refers only to valence or hedonic tone ; more explanation will be given later), believing that the affect representation is the core element of the emotional experience, and it and arousal arise from different mechanisms. The third chapter discusses the manifestation and the relevant mental phenomenon of cognitive representation and affect representation in the emotional experience , thinking the affect objectification is an important mechanism of emotional experience. Finally, based on the separability of cognitive representation and affect representation in emotional experience and sensory feeling, and based on the fact that a lot of researches show the homology of these two kinds of affect（in emotional experience and in sensory feeling) in the brain substrate, the article analyzes the possibility that the affect component in emotional experience derive from the conditioned response of the affect component in sensory feeling.

Emotion experience is a multi-component compound feeling

It is generally accepted that emotion is a multi-component process, including at least subjective experiences, expression behavior and physiological arousal（e.g., Izard，1991；Gross，& Levenson，1993）. The experience of emotion is an important part of the emotion process，so in-depth look at it is certainly an important way to understand emotion. First, this chapter lists some representative views about emotion experience by category，then analyses them respectively based on the existing experimental evidences and objective phenomena，and put forward a comprehensive conclusion.

Three types of views about emotion experience

1. Emotion experience is a body perception.
James: emotional states have specific and unique patterns of somatovisceral changes, and the perception of them constitutes an emotion experience (James, 1890). Tomkins: each discrete emotion is a set of motor and glandular responses（mainly located in the face）which is triggered by different subcortical affect programs，and emotion experience is the awareness of this facial feedback（Tomkins, 1962）. Izard:“A specific emotion is a specific facial expression, and our awareness of that facial expression is the … Subjective experience of emotion” (Izard，1977；p. 58).

2. Emotion experience is the compound feeling that consists of body perception and other perceptions
Maranon: an event evokes emotion, which leads to perception, which leads to sympathetic arousal, of which the person may become aware. The true emotion will only be experienced when the perceived arousal is joined with the initial perception（Maranon, 1924）. Mandler: emotion experience is a unified construction that combines a nonspecific arousal structure and an evaluative structure (i.e., cognitive interpretation of the situation). The awareness of arousal provides the intensity of the emotion experience，and the awareness of evaluative provides the particular content and quality of emotion experience（Mandler, 1984）. Damasio: the feeling of emotion depends on the juxtaposition /superposition of an image of the body proper to an image of vision or audition（Damasio, 1994）.

3.Emotion experience is the compound feeling of the awareness of hedonic tone（pleasure-displeasure, otherwise called as valence, positive or negative feeling) and other perceptions.
Leventhal: first of all，the individual has a feeling caused by external information, and this feeling is simply positive or negative rather than representing more precise categories of emotion experience. Later, more specific emotional discriminations occur and involve feedback from the expressive and autonomic systems（Leventhal, 1982）. Frijda: emotion experience is usually made up of the awareness of action tendency，of a autonomic arousal, of a hedonic feeling of pleasure or pain, of an appraised situation, and awareness of the emotion’s significance（Frijda, 1986）. Johnston：the shared element and remarkable attribute of all feelings—emotions and sensory feelings—are hedonic tone（positive and negative）.“…the presence of hedonic tone—pleasantness or unpleasantness—defines feelings and distinguishes them from all other types of conscious subjective experiences, like thoughts and sensations.”（Johnston, 1999;p. 62）. Russell： at the heart of emotion, mood, and any other emotionally charged event are core affect. Core affect is a primitive feeling that consists of valence（pleasure-displeasure）and arousal, and it can be experienced in relation to no known stimulus— in a free-floating form—as seen in moods，and can be experienced as a emotion by attributing it to an object or event. Barrett: the emotions such as anger, sadness, happiness and so on people will experience when core affective feeling, perceptions of meaning in the world, and conceptual knowledge about emotion are bound together at a moment in time to form a single unified percept, much like color, depth, and shape are experienced together in object perception（Barrett, 2006b）.

An analysis and integration of the above three types of views

With regard to the first type of view, it is acknowledged that the emotion process is usually accompanied with body changes and our perception of them, and there is really a high stability of the connections between different emotions and the different forms of visceral changes and facial expressions, and so it allows body perception to be an important differentiating factor to different emotion experiences（Scherer & Wallbott,1994）。However, while affirming the importance of the body perception in emotion experiences，it is open to doubt the adequacy of the body perception as emotion experience. A simple counter example is that, as Kalat and Shiota（2007） have pointed out, many non-emotional factors can also influence sympathetic nervous system activities. For example, when you walk up a flight of stairs, you also feel polypnea and heart pounding. Clearly, the body perception at that moment has no quality of emotion. This shows that the body perception is not sufficient for emotion experience. James once said: “Without the bodily states following on the perception, the latter would be purely cognitive in form, pale, colourless, destitute of emotional warmth ”（p. 248）.However, from the perspective that the perception of faster heartbeat, faster breathing and tense muscles that result from somebody doing physical exercises has no the property of emotion，the body perception itself is also pale and colourless，destitute of emotional warmth, and possess cognitive quality，in the absence of something.

Furthermore, in the studies of the people with spinal cord injuries who lost the ability of response and sensation of body in different degrees，most patients reported that their emotion experiences were as strong as before, especially fear and sadness (Chwalisz et al.,1988；Cobos et al.,2002). And the patients with Moebius syndrome, congenital loss of facial movement, have no apparent deficit in emotion experience，and their ability to recognize the facial expressions remains intact（Calder et al.,2000；Bogart & Matsumoto, 2010）. Even some patients with locked-in syndrome（people lose almost all output from the brain to the muscles and the autonomic nervous system except a few clusters of neurons control eye muscles）, reported（dictated by blinks of one eyelid） that they could feel a series of emotions from sadness to happiness（Damasio，1999）.

These are sufficient to show that although body perception is important to emotion experience, it is not sufficient，and even is perhaps not necessary. Obviously, in addition to the body perception, there are other more important mental contents in emotion experience.

From the perspective of function, we know that all kinds of emotion experiences contain a mental state of like or dislike that corresponds to the action tendency of approach or avoidance and is an important mental base of motivation. Based on phenomena, the connection between the other constituents of emotion experience and the mental state of like or dislike are not stable. For example, as the connection between body perception and its nature of hedonic tone, the perception of heart beat can also be either disliking (as the heart beat for fear) or liking (as the “heart beat in love”). And the like or dislike to a perceived external object changes with different people or time. The pleasure and the displeasure always correspond to like and dislike respectively. There is not the feeling of pleasure that we don’t like，and there is not the feeling of displeasure that we don’t dislike. This noticeable consistency suggests that the mental states of like and dislike may be intrinsic nature of the feeling of pleasure and the feeling of displeasure respectively. In fact，it may not be possible to distinguish the neural underpinning between hedonic tone and like or dislike in study. For example, the nucleus accumbens that is known as pleasure center is also thought to be the brain substrate that causes liking. Rozin（1999）defines pleasure and displeasure as: pleasure is “a positive experienced state that we seek and that we try to maintain or enhance.” Similarly, pain (or aversion) is “a negative experienced state that we avoid and that we try to reduce or eliminate.”（p,112）. In this definition, the pleasure or displeasure is the experienced state that we seek or avoid, respectively. The seeking & like and the avoidance & dislike are mentally related respectively，and even are the same. Therefore, this definition also seems to hint the close relationship between the hedonic tone and the like or dislike state. While this article favor such a definition：pleasure is a feeling entity that has its particular conscious quality（though we may not feel it alone，as we feel it in the perception of heart beat in love), and carries a mental state of liking(i.e., We seek and try to maintain or enhance it). And displeasure is a feeling entity that has its particular conscious quality（though we may also not feeling it alone), and carries a mental states of disliking (i.e., We avoid and try to reduce or eliminate it). In this mental seeking or avoidance there is clearly a nature of drive, in other words, the mental states of liking and disliking carried by hedonic tone are an inner drive that is just the basis for a motivation. It may be because of the existence of the hedonic tone which carries a mental states of liking or disliking so that the emotion experience has a motivational function to produce the action tendency like approach or avoidance, and the various emotion experiences themselves have a nature that arouses our seek or avoid. In effect, in the theory of the positive psychology that emphasizes the role of emotions, the functional accounts of positive emotions capture only the effect of pleasant subjective feeling and forsake the other aspects of the emotion.

In short，the hedonic tone whose mental representation are the simplex feelings of pleasure and displeasure is the most pervasive feature of emotion experiences, and it is because of its presence that the emotion experience is an emotion experience,and that other components coexisting with it in emotion experience possess the quality of the emotion. This shows the necessity of hedonic tone for emotion experience. The hedonic tone plays an important role in the productions of action urge and emotional motivation，and its intensity has a more essential connection with the intensity of emotion experience that often determines the intensity of a motivation. This shows the functional significance of hedonic tone for emotion experience. Therefore, based on the necessity and functional significance of the hedonic tone for emotion experience, it can be argued that the hedonic tone is the core component of emotion experience. Furthermore, hedonic tone is a substantive mental representation. It appears not only in emotion experience，and is also the shared element of all sorts of sensory feelings and moods, and is also generated by the changes in internal milieu and the drug action. The emotion experience may be the integrated experience formed by combining the hedonic tone that is not limited to emotion experience with some conscious contents.

So far, based on the above analysis and the theory of consciousness bonding problem, the conclusion that is more closer to the mental fact of emotion experience may be drawn only by integrating all the reasonable contents in the above views, and then combining some ideas of this article：the emotion experience is the multi-component integrated experience that is usually made up of the mental representations of hedonic tone, body perception, object perception, appraisal awareness and action tendency，among which the hedonic tone is core component. The hedonic tone defines emotion experience and its intensity has a more essential connection with the intensity of emotion experience，and it plays an important role in the productions of the action tendency in emotion experience. For example, the experience of a typical fear may be made up of the mental representations of a feeling of strong displeasure，the perceptions of muscle tension and rapid heart beat，the perception of a horrible environment or object, the awareness of “danger”and the awareness of urge to slink away or hide; and among them the feeling of strong displeasure defines this complex experience as emotion experience，and plays an important role in the production of the urge to slink away or hide. And the distinction between the experiences of different emotions may be embodied in the distinction between the actual contents of these components. For example, the experience of fear usually consists of the feeling of displeasure，the perceptions of muscle tension and rapid heart beat，the perception of a horrible object, the awareness of “danger”and the awareness of urge to slink away or hide; and the experience of sadness usually consists of the feeling of displeasure, the perception of sinking and cold heart, the faces of a deceased relative or friend in memory and the awareness of “loss”; while the experience of happiness usually consists of the feeling of pleasure，the awareness of “obtaining”and the awareness of urge to jump or embrace.

Nevertheless, for the multi-component integrated experience, its integrality is at the level of experience and is not as “solid” as the integrality of the perception of a “red circular apple”. As mentioned before, the combination in the level of perception is inseparable in consciousness, while the some components in emotion experience are separable, for example，we can be conscious that the body perception and object perception are separate in time and space. Whereas, the combination of hedonic tone with other components (particularly the body perception) is inseparable in consciousness，and this combination is in the level of perception. Furthermore, Lambie and Marcel’s analysis shows that the experience of each emotion can take different forms，and it depends on aspects of attention: mode (analytic-synthetic), direction (self-world), and focus (evaluation-action). Therefore, we sometimes may experience only the some components of a typical emotion experience，and will also treat it as this emotion experience.

chapter 2. Two different mental representations：cognitive representation and affect representation

As stated above, it is for the presence of hedonic tone that the emotion experience is an emotion experience, and it distinguishes emotion experience from simple cognitive perception in form. So, the so-called distinction between emotion and cognition in the form of perception lies in essentially the difference between hedonic tone and simplex cognitive perception. That is, if there are two kinds of mental representations with different forms, the two ones are the mental representation of hedonic tone and simple cognition.

We know that the simple perception, as a mental representation, is based on some basic sensations such as color, brightness, sound, body site, muscle tone, body movement and so on. These basic sensations arise mainly from the specific sensory systems of vision, hearing, touch, kinesthesis and so on，which constitute our various perceptions of our body and outside world, and allow us to recognize various objective features of our body and the things outside，and are also the basis for our concept formation and thought process. Therefore, these basic sensations and the mental representations of various simple perceptions，concepts and thoughts that are constituted by those sensations possess discriminative and cognitive function. In neural basis，these basic sensations have their specialized receptors, neural pathways and projection areas in cortices. And while the neurochemical bases are basically the same for all kinds of sensations, their specificity reflects in special cortical area.

Furthermore, for some sensations in the traditional sense such as pain，taste，smell and temperature(this paper uses Johnston’s way, calling them sensory feeling)，modern research has shown that they have both the component of specific sensation and the component of nonspecific affect or hedonic tone, and the neural bases of the two components are different. For example, modern research suggests that the pain stimulus causes two parallel ascending neural inputs. One projection derives from the deep dorsal horn through the lateral thalamus to somatosensory cortex, which producing the discriminative sensation of the pain, comprising its intensity，location and quality . The other projection derives from the superficial spinal dorsal horn through the medial thalamic nuclei to the anterior cingulate cortex (ACC) and the insular cortex ( IC)，which producing the pain affect（pain unpleasantness）. And clinical studies have confirmed that the sensation and affect components of the pain are detachable. For example，ablations of ACC and its underlying white matter, the cingulum bundle, reduce or abolish affective responses to noxious stimuli, while sensory localization remains intact, whereas patient with damage to somatosensory cortices is unable to feels pain (its intensity, location and quality) ,but feels an inenarrable unpleasantness. So, it is generally believed now that the pain perception comprises two independent components，pain sensation and pain affect. Similarly, for smell，taste and temperature, their sensory stimulus also cause two parallel ascending neural inputs respectively into their respective cortical sensory area and some common limbic regions，and respectively producing their respective specific sensations and shared hedonic component. Also，their sensation and hedonic components are detachable. For example，in an experiment that involved computer games and custom-made scents, researchers found that the responses to new odors depended on the emotions experienced while the new odor was present. If participants had a good time playing the game, they were more likely to report they liked the odor. If they had an unpleasant experience, they were more likely to dislike the scent. A cool glass feels wonderful if your body is hot, but it feels unpleasant if you chilled. And a taste that we usually very enjoy can become disgusting as well in some cases. Therefore, the same as emotion experience, the sensory feeling ( also including thirst, itch, the feelings of hard light and loud noise, and all kinds of the feelings comfortable or uncomfortable in body) can also be regarded as the compound feeling that consists of discriminative sensation and hedonic tone. Also therefore, the cognitive mental representation should as well include the discriminative sensation in sensory feeling.

And the hedonic tone as a mental representation, as previously mentioned, is the shared component element of emotion experience, sensory feeling and mood. In neural basis，every form of hedonic tone appears to be closely related to the change in the level of certain neurochemicals in the brain. Many studies have shown that the release of dopamine onto the nucleus accumbens appears to underlie almost every form of pleasure that we can experience. Delicious food, sexual behavior，addictive drug，transcranial electric stimulation and expectations for reward, they all can increase the level of dopamine in nucleus accumbens. And there are studies to show that endorphin is a source of pleasure, and its release is associated with a feeling of well-being and the feelings of pleasure produced by delicious food, exercise, orgasm and so on，and it can reduce or eliminate negative mood as well as all kinds of physical pain and mental anguish. And a study using positron emission tomography (PET) found there are robust reductions of endorphin in the rostral anterior cingulate, ventral pallidum, amygdala, and inferior temporal cortex, in response to the self-induced sadness state.

There is still a lack of understanding about some basic questions concerning hedonic tone. For example, how many kinds of pleasure and displeasure which are different in both feeling and neural substrate are there in the brain ? Or are there only one pleasure and one displeasure, and the differences in feeling is just because they blend in separately with different kinds of other mental representations？（e.g., the two kinds of pleasure from taste and from flesh may be the same, but their differences in our feelings are because the former blends in with the specific sensory component of taste and the tactile contents of food, and the latter blends in with the sensations from skin and muscle; and the displeasure of grief is different from that of frustration, “in that the former contains the lost object, whereas the latter contains the envisaged unachieved goal.”[Lambie & Marcel, 2002]） Can we feel the pure pleasure or displeasure without other mental representations? However, it is now almost certain that, contrary to the discriminative basic sensations that serves as the basis of cognition, the neural basis of the hedonic tone is nonspecific. For example, dopaminergic neurons in nucleus accumbens receive input from almost all receptors, and different types of rewarding stimuli elicit similar neuronal responses. Therefore, hedonic tone has no specialized receptor and neural pathway, and its presence is only related to the significant change in level of certain neurochemicals in the brain. The nonspecificity of hedonic tone may be the cause of its floatability (i.e., in our experience, the hedonic tone almost always blends in with other cognitive sensation, perception and concept, and so on).

So far, we can see that at neural basis there are two different basic mental representations: discriminative sensation and hedonic tone. The discriminative sensations include visual, auditory, olfactory, gustatory, kinesthetic, and the sensation component in various sensory feelings. Its production depends on specific receptors, neural pathway and their special projection area in cortices. By different sensations and the different levels of mental representations constituted by them, we can know the various properties, forms, changes and relationships of our own body and external objects. This is consistent with the general view that cognition reflects the objective features of ourselves and world. And the presence of hedonic tone only relates to the change in level of certain neurochemicals in the brain, and in consciousness, there are only two features or qualities of pleasure and displeasure that is of different intensities (however, we may be indeed unable to be conscious of them detached from other mental representations alone), and they are accompanied by the mental states of like and dislike, respectively. Hedonic tone is ubiquitous in various sensory feelings and emotion experiences, and strongly related to our physical need and mental desire, and reflects on the organism’s inherent needs. Therefore, this paper thinks that the cognitive representation could be defined by the specificity in neural bases. That is, the mental representations that are based on specific sensory systems such as simple sensation, perception and abstract idea， could be categorized as cognitive representation. And the hedonic tone as another form of mental representation, could be defined by the significant change in level of certain neurochemicals in the brain. And based on the analysis above and in chapter 1，this paper thinks that for the hedonic tone that a mental representation differs from cognition and is of universality, it is very suitable to be denoted by the word “affect” that is the most inclusion among the terms for emotional phenomena. That is, this paper thinks that there are two different forms of mental representations in the brain. One is cognitive representation including all the simple sensations and perceptions at present, in memory and in imagination, and the mental representations of general thinking activity. The other is affect representation（i.e., The mental representation of hedonic tone) that is present only as pleasure and displeasure in consciousness, carrying the mental states of like and dislike. And various emotion experiences and sensory feelings are the integrated feeling that is made up of the two mental representations. In the following chapters of this paper will use the related terms under these notions.

Cognitive representation and affect representation in emotion experience, and the phenomenon of the objectification of affect

The cognitive representations in emotion experience are some simple body perception, object perception, conscious appraisal，and the sensation component of some sensory feelings. The body perceptions and the sensation components in sensory feelings that often occur in emotion experience mainly include the awareness of tense muscles, faster heartbeat, breathing change，temperature within heart or stomach(as the cold feeling in heart when we are sad, the warm feeling in heart when we are delighted)，and so on. As indicated above，there is not the property of emotion experience in body perception itself, and the body perception in emotion experience should be part of our common body perception. Although the too cold or too hot temperature and too fast heartbeat can cause displeasure, the body changes in temperature or heartbeat for the emotional state are generally not more than the changes for that we drink a cup of cold water or run 100 meters. So the sensory feelings in emotion experience are almost all neutral, and there are mainly the sensation components of sensory feelings that occur in emotion experience. Moreover, there are the imaginations and intentions of motions in the mental representation of action tendency in emotion experience，such as attack, run, or embrace. It has been known that the preparation and execution of a motion require the sensory feedbacks from vestibule, vision and body, and the primary motor cortex is also the sensory area of muscle spindle. So the cognitive representations in emotion experience should also include the representations of motion and intention in conscious action tendency.

The object perception (including the perception of environment) can also blend in with emotion experience, like an object or environment of fear under a pall of terror. The object perception in emotion experience also includes the representations of memory and imagination, such as the faces of a relative or friend in memory in the experience of sadness and the scenes of future campus life in imagination in the experience of happiness when we received our university admission notice. As stated above, the appraisal awareness is also often part of emotion experience, and is an internal factor that evokes emotion. The appraisal process is a thoughts activity based on language and image, and the appraisal in emotion experience is also part of our common thoughts activity.

By these cognitive representations from body, external world and brain inside, we can acquire all kinds of objective information from our own body and world. These cognitive representations can either involve in emotion experience or exist alone. And as it is shown by some experimental results in chapter 1, they might play an important role in the distinction among different emotion experiences.

The affect representation（mental representation of hedonic tone) in emotion experience should be the rest of various emotion experiences when all cognitive representations were removed. Obviously, besides those cognitive representation, there is the pleasure or displeasure and the corresponding mental state of like or dislike in emotion experience. And the pleasure and displeasure are what we can not find in those cognitive representations that occur alone in non-emotion state, so they are the affect representations of emotion experience. The affect representation is the most pervasive feature of emotion experiences, and its intensity reflects the intensity of emotion experience more directly，and it plays an important role in the productions of emotional motivation. Given that the neural basis of affect representation is non-specific and the cognitive representation plays an important role in the distinction among different emotion experiences，the affect representation may be primitive and undifferentiated, and is present only as simple pleasure or displeasure that is of different intensities. And the mental states of like and dislike may be intrinsic to the pleasure and displeasure, respectively. Furthermore, as it blends in with body perception（like the perception of heart beat) in emotion experience, the affect representation has a floating character in consciousness, and we almost always blend in it with other representations and are unable to feel it alone.

In summary，there are many kinds of cognitive representations that often occur in emotion experiences, and they can reflect the various objective features of our own body and world respectively, and they themselves don’t have the subjective quality of pleasure or displeasure；the affect representation is the most pervasive feature of emotion experiences, and in consciousness, it is present only as pleasure and displeasure that carry the mental states of likes and dislikes, and has a floating character. So, if emotion experience is formed by combination of the two concurrent mental representations that are different in forms, it is inevitable that as the result of such combination，the floating affect representation is affixed to other cognitive representations, and the simple cognitive representations have a affect quality.

For example, when a neural representation that entails pleasant affect is triggered and there is also the sensory input of heartbeat (even if they are generated by different mechanisms), the conscious qualities and liking mental state of the pleasant affect may be affixed to the perception of heartbeat, which makes the simple perception of heartbeat become a “pleasant and likeable heartbeat”. Similarly, if it is the unpleasant affect that occurs concurrently with the perception of heartbeat, the felling of the unpleasant affect may be also affixed to the perception of heartbeat, and an “unpleasant and disliking heartbeat” will be experienced. This would explain why we will experience the pleasure or displeasure as an inherent quality of body perception and why the same body arousal is sometimes likeable and sometimes disliking when we are in emotion experiences.

And when we have a pleasant or unpleasant affect, if our attention at this time focuses on an external object, especially on an object that is (or thought to be ) directly related to the production of this affect, the feeling of the affect may be affixed to the perception of this object, which makes the simple perceptual object become a “pleasant or unpleasant object” in our experience, and turns our liking or disliking for our pleasant or unpleasant affect into our liking or disliking for this object. This would explain why the same object is pleasant and lovable in some people’s eyes, but bland in others’eyes, and even in the same person’s eyes, it’s changeable with time that the same object is loveable or not. Winkielman et al., (2000) provided evidence that the pleasure (induced through subliminal stimulation) can emerge into consciousness as a mood in some circumstances but as liking for a beverage in other circumstances. This can also be the evidence for the floating character of affect representation. So，the body perception and object perception we experience in various emotions are actually the body perceptions and object appearances that are affixed by the affect representation of pleasure or displeasure.

Santayana（1896）had put forward such a famous definition of beauty:“beauty is the objectification of pleasure.” that is,“Beauty is pleasure objectified – pleasure regarded as the quality of an object.” Now at least we have reason to believe that an object itself is not of the pleasant or unpleasant quality in perception, and we will perceive an object as the pleasant or unpleasant after we have a pleasant or unpleasant affect. Therefore, for the mental phenomenon that the affect representation is affixed to body perception or object perception, it can borrow Santayana’s way to call this as the objectification of affect. In such mental phenomenon, an affect representation will be bound to cognitive representations which possess objective features, which makes us experience the conscious quality of affect as the quality of body perception or object appearance and turn our liking or disliking state of affect into our liking or disliking for our body perception or an external object.

In fact, it is a more common mental phenomenon that some mental contents from different sources blend together in a current perception. For example, many tastes are a composite of gustatory and olfactory information. And the visual texture and the cool and warm in colors contain the experiences of touch. Even some abstract concept can also be affixed to current perception. For example, Rowe (1978) recorded an individual with depression who reported: “At that time ordinary objects—chairs, tables, and the like— possessed a frightening, menacing quality …” (pp. 269–270). In fact, it is a shared characteristic of many people with depression that see a menacing quality from unrelated objects. In this case, the concept of menace does not simply appears in the patients’ mind, but it is integrated into various object perceptions, and becomes a quality or property. Although most of us are free of depression, there are no significant difference in the neurological basis of the brain between we and people with depression. In normal mental activity, there are many examples of so-called aesthetic empathy such as the “dignity” of golden-colored, the “elegance” of rose and the sense of “rise” and “strength” in ancient Greek stone pillars. We seem unable to distinguish whether these are just our associations or internal feelings，or are the visual properties of those objects in our immediate experiences.

As for the action tendency in many emotion experiences, it should be the mutual product of cognitive representation and affect representation. The action tendency of approach or avoidance to an object is the basic form of motivation. It requires a perception of an object, an imagination of a set of motions and a drive of doing that motions. Here the perception of an object and the “motions” in imagination are cognitive representation, and they provide action object and motion planning. And the action tendency of approach or avoidance corresponds to the mental state of like or dislike (a inner drive) that is carried by affect representation, and what this reflects is the connection of liking-approach, disliking-avoidance that are between like or dislike state of affect and action tendency. The formation of this connection may be based on learning. Research suggests that some automatic actions and emotional responses that are seemingly built-in may actually be acquired. For example, wild-caught rhesus monkeys fear and avoid snakes, but laboratory-reared monkeys don’t have that responses. Laboratory-reared monkeys will rapidly acquire a fear of snakes if a videotape on a wild-caught monkey is afraid of snake is shown. Even so-called pain withdrawal reflex may be also acquired. For example, the dogs reared in a sensory deprivation environment made not any movements of withdrawal reflex except localized reflexive jerks when the dogs were pin-pricked. It seems that the formation of the pain-withdrawal connection will exist only after they acquire the experiences that their pains are reduced or eliminated when they withdraw from the source of the pain.

In addition, although many theorists believe that the body changes which leads to body perceptions in emotion experiences is produced by innate brain devices which produce emotions, it does not exclude the possibility that they are entirely caused by some realistic reasons. For example, sports physiology experiment have shown that when people are imagining doing sports, there are similar body changes as the actual body sports，merely in low intensity. Other study has also found that before training, due to the stimuli of athletic field environment and music, the athletes will have the conditioned reflexes such as a rise in heart rate, blood pressure, and breath frequency, which is induced by the conditioned stimuli formed in similar circumstance that there are body changes in sports training. Moreover, before winter-swimmers getting down to swimming，the regulatory mechanism of homoiothermism has been launched in advance by visual stimulus of the circumstance，and heat production is increased and heat dissipation is reduced. These conditioned reflex activities are also called feed forward adaptive control，which seem to make the body responses have the foresight, and ready to prepare for physiologic adjustment reaction as early as possible.

In summary，the objectification of affect is an important mental phenomenon in the process of emotional experience. In such mental phenomenon, our affect representation shows up as a quality（pleasure or displeasure）of body perception, or, as one of perceptual features of a object (pleasant or unpleasant), turning liking or disliking mental state in affect representation into our liking or disliking for our body perception or an external object. And our emotional experiences such as fear, anger, happiness and sadness may be the integrated experiences of the combinations of various affect representations, body perceptions, object perceptions, appraisal awarenesses and action tendencies that occur relatively simultaneously.

A possible mechanism: the production of mental affect is the conditioned response of physiological affect

As stated above, emotion experience and sensory feeling are the compound experience or feeling formed by the combination of cognitive representation and affect representation, and the production of their affect components is all related to the obvious changes in the level of dopamine and endorphin in nucleus accumbens, amygdala, ventral pallidum and anterior cingulate. This suggests that there may be the homology in brain substrate between the affect in sensory feeling(hereinafter referred to as physiological affect for it often arises from direct physiological stimulus) and the affect in emotion experience( hereinafter referred to as mental affect for it is usually produced by mental activities such as anticipation and appraisal). For example, Schultz et al. found that dopamine neurons were activated when naive monkeys tasted a small morsel of apple or receive a small quantity of fruit juice to the mouth. After repeated pairings of visual cues followed by reward, dopamine neurons change the time of their phasic activation from just after the time of reward delivery to the time of cue onset. In this case, if the activation of dopamine neurons will produce pleasure in the monkeys, then the former is gustatory pleasure (physiological pleasure) and the latter is the pleasure that is produced by visual anticipation (mental pleasure). The two kinds of pleasure are homology in brain substrate. In addition, the dorsal anterior cingulate cortex (dACC) has been characterized as a distress center, producing activity to instances of both physical and social pain; antidepressants have similar effects on alleviating both mental anguish and physical pain. Based on these facts, Eisenberger and Lieberman（2005）put forward a pain overlap theory, and they argue that physical and social pains share a common phenomenological and neural basis.

At present, it is almost certain that we have the innate neural pathway that produces the physiological affect in sensory feeling, such as the neural pathway that produces pain affect mentioned above. For sensory feeling, while a stimulus produces the discriminative sensation through distinct sensory pathway, it also directly produces physiological affect through a parallel ascending neural inputs to limbic subcortical regions, and the discriminative sensation and the combine of the affect forms various whole sensory feelings; and there are significant consistency between various stimuli and the subjective nature of affect (pleasure or displeasure) that they produces. Therefore，it is no doubt that the physiological affect can be produced by innate mechanism.

Whereas for emotion experience, there are a large number of experimental researches on the innate neural pathways that produce various emotions(and the experiences of them ) since last century, but researchers have not found any reliable neural pathway that is dedicated to generating any discrete emotion (for a review, see Barrett & Wager 2006b; Russell, 2003). And the emotion experiences are usually produced by the visual and auditory information. Unlike the sensory feelings, there is lack of the consistency in the relationship between the subjective nature of affect in emotion experience and the sensory inputs from vision or hearing, sometimes even opposite. For example, a bear we see in the wild and at the zoo will give us two different kinds of emotion experiences, fear and interest, which are completely opposite affects in the subjective nature. Therefore，it is very possible that we have not the innate neural pathways at all that can directly correspond to any environmental stimulus and produce our mental affect.

So, what is the acquired mechanism that produces mental affect through vision or hearing, or in other words, how do the processes of vision or hearing connect postnatally with some neural structures in limbic regions? And if the affect in emotion experience is produced by the mental activities such as anticipation and appraisal, and how do they produce the affect? In fact, the second question is essentially equal to the first question because our mental activities (including cognitive appraisal) are mainly operated on the basis of the neural representations that entail visual and auditory representations（including the literal and voice representations of language). And considering that the sensory feeling and emotion experience are the compound feelings that consist of separable cognitive and affect representation, and their affect components share a common brain substrate, we can answer this question by the hypothesis : for an individual today, the production of his every mental affect is the conditioned response of his physiological affects.

It is already a general scientific knowledge that conditioned reflex can be established between any different nerve processes that occur at the same time or in succession，including between the neural processes of cognition, emotion and sensory feeling, and even between the nerve processes of mental activity and physiologic change. We know that it is a conditioned response that saliva will be produced as we see gourmets. This is because our vision process about gourmets had established nerve connection with the process in hypothalamus that control salivation as they took place at the same time or in succession when we was eating gourmets in the past，and when we see gourmets again, this vision process may cause the conditioned response of the correlated nerve process in hypothalamus to stimulate the secretion of saliva. It is worth noting that we also usually have an emotion of happiness and the liking for the gourmets at this time. That is, we are experiencing an emotion of happiness that is made up from at least the two mental representations of the gourmets and a pleasant affect, and turn our liking for this pleasant affect into our liking for the gourmets. Then, how is the pleasant affect in this emotion of happiness produced? One possible reason for this is that the production of this pleasant affect is the conditioned response of the physiological pleasure that was produced in the processes of our previous taste and smell when we were enjoying the delicious food in the past. That is, while our present vision process about gourmets activates the nerve process that controls salivation（its conditioned reflex is provoked）, it also activates the old physiological affect in the previous sensory feelings of taste and smell that have been contacted with the process similar to this vision process in the past. In fact，the finding of Schultz et al. mentioned above can also be the supporting evidence that mental affect may be the conditioned response of physiological affect. In this finding, the activation of dopamine neurons by visual anticipation in naive monkey is obviously a conditioned response of the activation of dopamine neurons caused by previous gustation. So, according as the conditioned reflex is the common phenomenon of neural activities, we could argue that because our certain visual or auditory process and the process of our certain sensory feeling once occured at the same time or in succession，it may activate the old physiological affect in this sensory feeling when the similar visual or auditory process occurs again at a future time ( from previous discussion we know that the sensation and affect in sensory feeling are separable, and their nerve bases are housed in different brain areas, so it is possible that their respective conditioned reactions can occur separately), and then the mental affect is produced. And our various emotion experiences may be formed by the combination of the mental affect which is the conditioned reactions of physiological affect and some other present mental representations.

For example, although there are the cases of conditioned pain in clinical practices, e.g. a ballet dancer felt toes pain as soon as she heard Tchaikovsky’s Swan Lake, this type of phenomenon is very rare. The conditioned response of pain is usually displayed in another form. That is, what the conditioned stimulus related to pain produces is generally not the original body pain, but the feeling of fear. For example, after the repeating associations between fur and pain, the sight of fur will evoke the feeling of fear but not the feeling of pain. Another situation is that if a loud noise is repeatedly presented whenever a child is shown a furry animal, the sight of furry animal will soon evoke a feeling of fear, rather than the sensation of loud noise. Johnston（1999）summed up these results of classical conditioned reflex as that the common element between a loud noise and pain is their shared unpleasantness, and it is the acquired association between the conditioned stimulus and unpleasantness that evokes a fear response. And under the concept of this paper, this phenomenon can be interpreted as that the conditioned response of the sensory feelings of pain and loud noise are usually just their a component of affect rather than a whole sensory feeling. And the formation of this fear emotion is the result that the unpleasant affect, which is evoked by conditioned stimulus alone, integrates with the percepts of conditioned stimulus and related body changes.

Take for example the experience of fear that is produced when a child sees nurses in the hospital, its unpleasant affect may be the conditioned response of the pain affect in the feeling of pain that is induced by the injections in his past. Its possible generation mechanism is that because the feeling of pain and the visual perception of nurses in white always appeared together when he received injections in the past, the neural connection are established between the visual perception and the pain affect. So, in certain conditions, when the visual stimulus of a nurse appears again and activates its old similar visual perception (it has been known that the formation of a new visual perception depends on the reactivation of old similar visual perception）, the old visual perception also causes the reactivation of pain affect that has established neural connection with it, so the intense unpleasant affect is produced. At the same time，as a result of other conditioned responses and the action tendency of avoidance that is based on the connection of disliking-avoidance, a series of activities in the motor system and autonomic system are produced, which excites the body changes of muscle, heart beat, respiration and so on, and their sensory inputs. When the above three mental contents that occurs at the same time are combined together, then it is formed that this emotion experience of fear that there is a visual image of nurse, an intense unpleasant affect，and those body perceptions and the tendency of avoidance.

So far we’ve seen that our brain can produce mental affect by the conditioned response of physiological affect and combines it with some other mental representations to forms various emotion experiences even without those innate mechanisms of basic emotions. If this is the truth of mental activity, it is easy to imagine that when the initial connections have been established between the physiological affects in limbic system and those basic cognitive forms such as visual and auditory representations, it builds a bridge to produce mental affect through more complicated cognitive processes (including the thought that is mainly operated on the basis of visual and auditory representations) ，thus enables the physiological affect to be indirectly activated in more roundabout and intricate ways，and then forms all kinds of more complex emotion experiences with current perceptions.